Sound propagating device



Sept. 22, 1931. L. E. BARTON sounn PROPAGATING DEVICE Filed Oct. 4, 1929 INVENTQR L. E. BHRTON BY Va ATTORNEYS H. J10 My Patented Sept. 22, 1931 LOY E. BARTON, F COLLINGSWOOD, NEW JERSEY' i scum) raoraenrme DEVICE Application filed October 4, 1929. Serial No. 397,309.

This invention relates to sound propagatmg devices.

t is among the prime objects of the present invention to provide a novel and improved sound propagating device which is tuating the same.

Other objects of the present invention include the combination and interrelation of parts whereby the whole forms a novel, simple and improved structure adapted to provide a loud speaker which willfaithfully reproduce sound waves at a high volume level.

Other objects and features of the present invention will be apparent from a consideration of the following specification taken in conjunction with the accompanying drawings, in which I Figure 1 is a vertical sectional view through one form of the present invention;

Fig.2 is a sectional view taken on the lines 22 of Fig. 1; j r

Fig. 3 is a sectional view taken on the lines 3-3 of Fig. 1. Referring more particularly to that form of the invention herein disclosed the device includes a conical surface 10, which may preferably be formed of paper or other suitable material and which is adapted to vibrate, thus to propagate sound waves in the conventional manner of a cone speaker. The surface 10 is adapted to'be actuated from a coilll, by means of an interconnecting driving tube or cylinder-12, the cone end of which is provided withreturn bent flanges 13, which engage the inner face of the surface 10 at the pointindicated, which point will be seen to be symmetrically spaced from the apex of the surface. The tube may be cemented or otherof circumferentially' spaced points.

wise suitably joined with the surface whereby a oining equal to the circumference of the tube is provided. Associated with the driving tube l2, furtherme'ans for delivering periodic rectilinear motion from the tube to the surface for vibrating the same is-provided, which means includes a truncated cone 14 cc mented or otherwise joined to the tube as at 15 and extending forwardlyand outwardly therefrom tobe oined with the surface as at 16. The joining of the surface with the trun cated cone 14-is preferably similar to the joining of the tube with the cone, whereby a circumferential cementunion is provided.

A further reinforcing and vibration imparting structure is provided in conjunction with the surface 10 and the cone 14, which includes a cylindrical member 17 concentrically spaced from the tube 11, its forward end being joined with the surface 10 at 16, with the forward end of the cone 14, while the rear end of the tube is joined by a member 18 preferably formed integral therewith, to the surface 10, as at 19. i The member 18 isin the form of a second truncated cone concentric with the truncated cone 14, the arrangement being such that upon vibration of the coil 11, the tube 12 will be rectilinearly moved and will impart its vibration to the cone surface through the joints 13, 16 and 19, which by virtue of their interconnection, simultaneously actuate the cone at aplurality The periphery of the cone surface is joined to a suitable flexible member 20, j as at 21, the member 20 being secured upon a frame 22 by a suitable securingrim 23.

In someinstances, particularly in the use of a large ,cone with a large driving tube 12, it may be preferable to provide a further reinforcingand vibration imparting structure within the driving tube, so that the apex of the cone will be caused to vibrate in unison with the surrounding surface. In such instances, the internal structure as here shown is utilized, which consists of a small internal tube 12 joined 'tothe cone concentrically thereof and near its apex as at'13 The rear end of the tube 12 is connected to the tube 12 by a frusto-conical structure 14", the

e pen u has structure 14 being joined to the rear end of the tube 12 and the forward end of the tube 12, as at 15 and 16 respectively. It will be i seen that the internal structure is structurally equivalent to and functions as the other tubular members carried upon the truncated portions 14 or 18, whereby the whole'vibrating Surface of the cone will be caused to vibrate in unison as distinct from thevibrations of the apex of a cone which pass from the apex outwardly. It willfbe' understdod that the invention isnot confined to the use of the internal structure but that the use of the strucq ture is controlled by the characteristics of the cone. i

For supporting thecoil 11 and the-associated freeend ofthe tube 1 2 in the usual circular gap- 24'of the electromagnet, actuating unit, generally indicated by. the numeral 2 5, a plurality of supportingthreads 26' are provided which are joined as atEZ/Z, to the tube 12, while their opposite ends'are supported upon suitable fingers QSassociated with the unit 25. The arrangement is such that the desired tension may be'placed'upon the threads to support the coil'accurately in the center of the air gap in such manner that the coilmay not move radiallybut is free to move rectil-inearly. It will be seen that the member 'is also free to 'move with the tube-.- ,1t will furtherbe-seen thatthe restoringiforce of the supports 26 and 27 in a direction parallelto thetube is so lowythat the natural period of the'structure with the surface 10', is below any voice or musical frequency. v

it It is well known that'iin order to obtain high volume of-sound reproduced from electrical impulses byumeansof a diaphragm,

there-must be a large area of projecting surface or its equivalent, and a fair degree of amplitude'in the motion of the diaphragm. If amplitude of motion is increased to; get high volume, considerable energy maybe transferred to the air from a relatively-small projecting surface, but the sound will/be at a high 'pressufre,.-which is undesirable. On

the other hand, if the areagof the projecting surface is increased, the diaphragm'usually rattles, or vibrates locally, giving rise to noises, and the high frequency impulses 7 travel from the source along the diaphragm in-the' form of progressing waves until the outer edge of the diaphragm is reached. lhe progressive-travel of the higher frequencies frozmnthe source causes interference ofsound' progejcted {from the sdlaphra'gm'at different instances, aswell as reduces theeifective area of the rojecting u a A 'lfrthe actuating "force of the coil is applied only at 'a point near thelvert exjof the sound projecting surface, 1 the impulse 'must travel along the projecting surface to the outer edge of the cone, thus creating considerable phase difference between the sound produced at the point of application and at the edge of the cone for large diaphragms, and at the higher frequencies. If, however, the actuating force is applied to the sound projecting surface by means of suitable links to essentially all parts of the diaphragm, and the links are of the same material and have practically the same, length to the projecting surface from the actuating coil, all impulses will reach essentially all .points on the sound projec'ting surface simultaneously,

quencies. The multiplicity of points on the sound projecting surface also prevents rattle of the surface, or local vibrations that are more or less independent of the movement of the diaphragm as a whole when, large diaphragms V are used.

Another characteristic of the reenforced structure is that due to the shape of the sound projecting surface, there is practically no directional effect in the projection of sound at any frequency. 1 r l I From the foregoing it will readily be seen that the inventionprovides "a novel, simple and improved sound propagating device which is adapted to minimize the propagation of parasitic wave formations and to provide for faithful reproduction -of'sound waves. In connectionwiththe invention, it'will be understood thatthe device is not confined to the specificstructural details herein enumerofconcentrically arranged tubular members engageable with said-diaphragm;

2. In a sou d propagatmgapparatus, the

combinationwith a conical sound propagating diaphragm, of an actuating unit'associated therewith, said unit includinga plu- ,raliin of concentrically arranged tubular members engageable with said diaphragm, each of said tubularmembers'being in axial '75 thereby causingthe sound projectingsurface, whic may be large, to move as a Whole at all frealineinentf with the aXisjof said diaphragm and contacting with the diaphragm over the entire circumference of one end thereof.

In a sound propagating device, the com binat-ion-with a diaphragm, of actuating means therefor, including-a tubular driving arm secured to said diaphragm, and mmcated conlcal member dlverging from said arm and engageable with said diaphragm.

' 4. In a sound propagating device, the come bination .With a; diaphragm, of actuatingmeans therefor, including-a tubular driving 13$:

arm secured to said diaphragm, and a truncated conical member diverging from said arm and engageable with said diaphragm in spaced relation to the engagement of said tubular arm.

5. In a sound propagating device,the combination with a diaphragm, of actuating means therefor, including a tubular driving arm secured to said diaphragm, and a truncated conical member diverging from said arm and engageable with said diaphragm in spaced relation to the engagement of said tubular arm and concentric therewith.

6. In a sound propagating device, the combination with a diaphragm, of actuating means therefor, including a tubular driving arm secured to said diaphragm, a truncated conical member diverging from said arm and engageable with said diaphragm in spaced relation to the engagement of said tubular arm and concentric therewith, a second tubular arm carried by said truncated member, and diaphragm-actuating means carried by said second arm.

7. In a sound propagating device, the combination with a diaphragm, of actuating means therefor, including a tubular driving arm secured to said diaphragm, a truncated conical member diverging from said arm and engageable with said diaphragm in spaced relation to the engagement of said tubular arm and concentric therewith, a second tubular arm carried by said truncated member, and diaphragm-actuating means carried by said second arm, said means including a second truncated conical mem- 8. In a sound propagating apparatus, a conical diaphragm, and a plurality of concentrically arranged tubular engaging actuating means each of said tubular means engaging the diaphragm for the entire circumerence of one end thereof.

9. In a sound propagating device, a conical diaphragm, and means for simultaneously actuating said diaphragm at a plurality of points, said means including a plurality of concentrically arranged tubular members associated with said diaphragm each of said tubular members engaging the diaphragm fgr the entire circumference of one end there- 0 10. In a sound propagating device, a conical diaphragm, and means for simultaneously actuating said diaphragm at a plurality of points, said means including a plurality of concentrically arranged tubular members associated with said diaphragm, an intermediate one of said tubular members extending rearwardly from said conical diaphragm for association with an actuating means.

LOY E. BARTON. 

